Simple variable check in function not making any sense...

[yduk]

Hey,

Ok I am creating a shopping cart and I am having a problem with something. When a user goes to their basket, they can edit their quantity for items, I need a way of checking that what they enter in this textbox is a numeric/integer value.

For example, if they type in t4, I want it to strip the t and put 4 in the value...

If they type ta or anything that is not numeric, I want it to leave the value alone.

This is my current code for modifying products:

// Modify quantity of cart if done in checkout
function modify_quantity($product, $quantity) {
    
    // Make sure quantity is an int
    $quantity = $this->check_int($quantity);
    
    // Quantity is less than 0, delete item from cart
    if($quantity <= 0) return $this->delete_item($product);
    
    // Limit amount of products to be ordered at one time
    if($quantity > 30) return false;
    
    // Check if quantity selected is greater than available
    $chk = $this->check_quan($product, $quantity);
    
    // Quantity selected is lower than available, ok
    if($chk == 1) {
    
        // No problems, update users cart
        $query= "UPDATE tbl_basket
                SET fld_amount='".$quantity."'
                WHERE fld_cartid='".$this->cart_id."' AND fld_pid='".$product."'";
        
        mysql_query($query, $this->dblink) or die ("Cannot select required information. "
            // .mysql_error()
        );

        return true;
    
    }
} // end function 

Now I have tried all kinds of things for is_numeric to is_int etc, nothing seems to work...

This is the function I am currently trying out:

function check_int($value) {
// use this function to make sure a value is of the correct format (int)
    
    // value is an integer, use it
    if (is_numeric($value))
    { 
        // Make sure value is numeric and change into an integer
        $f_value = settype($value, 'integer');
        
        return $f_value;
    
    // value not an integer, do not use
    } else {
    
        return false;
    
    }
    
} // end function 

Problem is, if I type in a letter, it removes the item from the cart, and if I put in an integer to update the quantity, it does nothing...

Any ideas?

Cheers,
Chris

[guido2004]

You might try using a regular expression.
Look here for examples: http://www.regexlib.com/